Cypermethrin
Cypermethrin is a synthetic pyrethroid ectoparasiticide used to treat infestations by external parasites such as lice, mites, and ticks. It works by disrupting the nervous system of these parasites, leading to their death. This medication is available in various topical formulations for both human and veterinary use.
A topical ectoparasiticide used to eliminate lice, mites, and ticks by disrupting parasite nerve function.
Key facts at a glance
- ATC
- P03BA02
- RxNorm
- 2590266
- Generic
- Cypermethrin
- Class
- atc-p03
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- topical
- Forms
- ointment, spray
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- N/A - Cypermethrin is an insecticide not typically used for systemic human treatment
- Maximum
- consult physician
- Frequency
- N/A
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- N/A - Cypermethrin is an insecticide not typically used for systemic human treatment
- Maximum
- consult physician
- Frequency
- N/A
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- N/A - Cypermethrin is an insecticide not typically used for systemic human treatment
- Maximum
- consult physician
- Frequency
- N/A
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesteravoid exposure
avoid use during pregnancy; if exposure occurs, minimize contact and ensure adequate ventilation
routine prenatal care
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid exposure
avoid use during pregnancy; minimize occupational and domestic exposure
routine prenatal care
Use with caution and monitor for adverse effects.
lactation
breastfeedingavoid direct contact
avoid breast milk contamination; wash hands thoroughly before handling infant
monitor infant for unusual symptoms
Use with caution and monitor for adverse effects.
pediatric_age
infantsavoid use
avoid use around infants and young children; ensure proper ventilation
observe for neurological symptoms
Use with caution and monitor for adverse effects.
pediatric_age
children 2 12 yearsavoid use
avoid use in pediatric populations; keep products out of reach
observe for skin irritation or neurological symptoms
Use with caution and monitor for adverse effects.
geriatric
elderly over 65use with caution
use with caution due to potential reduced hepatic metabolism; minimize exposure
monitor for neurological symptoms
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderatestandard use
no major dose adjustment needed as primary excretion is hepatic
general monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateuse with caution
use with caution; cypermethrin is metabolized in liver
monitor liver function
Use with caution and monitor for adverse effects.
alcohol_users
chronic alcohol consumptionavoid concurrent use
avoid exposure while consuming alcohol; alcohol may enhance absorption and liver toxicity
monitor for neurological and hepatic symptoms
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
Chemical class
Chemical classification as pesticide
Primary use
Primary application as pesticide
Human medical use
No human drug approval status
Used for the treatment of scabies, head lice, body lice, and pubic lice in humans; and ectoparasitic infestations including fleas, ticks, and mites in companion animals and livestock.
Cypermethrin is a neurotoxin that acts on the peripheral nervous system of parasites. It prolongs the opening of voltage-gated sodium channels, causing hyperexcitability, paralysis, and eventual death of the ectoparasite.
For topical use only; avoid contact with eyes and mucous membranes. Use with caution in cats, as they are particularly sensitive to pyrethroids. Do not ingest. Wash hands thoroughly after application. Consult a healthcare provider or veterinarian before use in pregnant or nursing individuals or young children.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy